Recently, various devices, such as a printer and a facsimile, are connected to a network. A printer acquires document data as a target of printing from a terminal. A facsimile acquires facsimile data. Alternatively, if the facsimile has a telephone function, the facsimile may acquire (record) a message of a party on the other end. Hereinafter, document data, facsimile data, and the like, are generically referred to as “content.” Devices which acquire content, such as a printer and a facsimile, are generically referred to as “content acquisition device” or “network device”.
Acquired content is managed by the network device itself or by a content management device communicably connected to the network device. The “content management device” is hereinafter referred to as a “management device.” It is advantageous for the network device or the management device to be able to search for a desired content among a plurality of managed content. In order to search for a desired content, the network device or the management device stores content in association with a keyword for searching purpose. Herein, the keyword for searching purpose is referred to as a “search keyword.” The user designates a search keyword in accordance with content.
Japanese Patent Application Publication No. 2005-20256 describes a management device that is easy for the user to designate a search keyword. The management device is connected to an image reader (a kind of network device) through a network. The image reader generates a reduced-size image of received image data (image content) and transmits the image to the management device. The management device extracts a characteristic quantity from the received reduced-size image and extracts candidates for a keyword associated with the reduced-size image in accordance with the characteristic quantity. The thus-extracted candidates for the keyword are sent to the image reader. The image reader displays the keyword candidates. The image reader sends to the management device a candidate designated by the user from among the candidates and acquired image data. The management device stores the keyword candidate designated by the user and the image data in association with each other. That is, the management device stores the keyword candidate designated by the user as a search keyword.
The technique of the Publication makes it easy for the user to designate a search keyword; however, search of image data (image content) is not necessarily easy. If keywords are provided for the user as in a case where a search keyword is designated even when image data are searched, so many keywords are provided for the user. Undesignated keywords as well as the keyword designated by the user in the past are also provided. In this case, it is consumed much time to find a keyword for searching for desired image data from the thus-provided keywords. In other words, providing a plurality of keywords, which may be relevant to content but have never been designated as a search keyword, to the user at the time of search of content assigned the keyword, causes user confusion. There has been a desire for content management technique that facilitates not only designation of a keyword but also search of content with a designated keyword.